The invention relates to a keypad structure for a communication terminal. In particular the keypad assembly has a plurality of keys being interconnected by a foil. The keys have activation pins cooperating with switching means whereby the switching means are closed when the respective key is depressed.
This kind of keypads is very attractive because the manufacturing costs are low. However this kind of keypad has a drawback because the foil is very flexible but not extensible. Therefore the depression of one key will cause a movement of the neighbouring keys due to the stiffness of the foil when the key is pressed. Therefore the keypads will have a cheap appearance.
An object of the invention is to provide a support structure for a keypad. The structure shall allow use of a plastic film keypad with in-moulded keys without affecting the overall quality appearance.
This purpose is obtained by a keypad structure for a communication terminal comprising a keypad assembly having a plurality of keys being interconnected by a foil, said plurality of keys are provided with activation pins, a keypad base part having switching means being activated by an associated activation pin when a respective key is depressed, and support means arranged in between the keypad assembly and the keypad base part supporting the foil of the keypad in between the keys. Hereby the depression of one key will cause a sideways movement of the neighboring key due to the force applied to the foil when the key is pressed. The keys will extend through openings in the front cover and will therefore not move due to the sideways draw. Instead the draw in the foil will be absorbed by elastic deformation of the foil surrounding the intermoulded keys.
The invention furthermore relates to a handset having such a keypad. The cost of the keypad may therefore by reduced substantially without negatively affecting the feel and appearance.
According to the preferred embodiment keypad is used in a cellular phone having exchangeable covers. The keypad assembly is maintained in a sandwich structure in between the releasable front cover and an inner housing cover. The user will be allowed to handle the keypad when he changes the front cover and the foil cover is very robust and therefor very attractive in this situation.
Preferably the support means are formed as pins and support areas on the inner housing, and said pins and support areas are raised relatively to the surrounding part of the inner housing cover. The switching means may advantageously be provided as switches on a printed circuit on a Printed Circuit Board covered by a resilient metallic dome means, whereby the switches are closed when the metallic dome means are depressed by means of the depression of the associated key.